In מגילה דף יב (Megillah 12a-b) it gives two reasons as to why Vashti did not go to Achashveirosh when he requested her to the party. The first reason is that Vashti had Tzarat (a metaphysical skin ...

The Gemara in Megila 6b says that if someone tells you that they understood a piece of Torah and they didn't work hard for it you shouldn't believe them.
The Ramha"l says in the Hakdama to his magnum ...